Short term outcome, complications and average direct cost in managing extremely low birth weight infants in a tertiary care centre in Sri Lanka

Introduction: Data on cost, short term complications and outcome of Sri Lankan extremely low birth weight (ELBW) babies is largely unavailable. Objective: To determine the cost, selected short term complications (surfactant treated and untreated) and short term outcome of ELBW infants in a tertiary care unit in Sri Lanka. Design, setting and method: A descriptive longitudinal study was carried out at Castle Street Hospital for Women over a 6 month period on all ELBW infants, excluding babies who were born after less than 23 completed weeks of gestation and babies who were transferred from the unit. Results: During the study period there were 39 ELBW babies. Ranges of birth weights and maturity were from 540g to 980g (mean 853g) and from 25 weeks to 34+3days respectively. Fifty one percent were small for gestational age. Survival rate was 76.9% at discharge. Hospital stay, intensive care unit stay, duration of mechanical ventilation and supplemental oxygen were 60.6, 13, 3.5 and 9.0 days per survivor respectively. Direct cost per survivor was SLR 82,207. Incidences of complications were 19.4% intraventricular haemorrhage, 8.3% necrotising enterocolitis, 22.2% pulmonary air leak, 11.1% pulmonary haemorrhage and 2.7% patent ductus arteriosus. Average weight gain on discharge was 5.2g/kg/day. Conclusions: Overall survival rate was 77%. IVH was significantly less in surfactant treated babies. (


Introduction
Extremely low birth weight (ELBW) infants are those that weigh less than 1000g.Very low birth weight (VLBW) infants (less than 1500g) account for over 50% of neonatal deaths and 50% of handicapped infants; their survival is directly related to birth weight with approximately 20% of those between 500 and 600g and over 90% of those between 1200 and 1500g surviving in the United States 1 .Although the rate of low birth weight is available, we do not have a national figure for VLBW or ELBW.Castle Street Hospital for Women (CSHW) in Colombo caters for more than 18,000 births annually and in 2008, 3,344 babies were admitted to the neonatal unit of the hospital out of which 326 (9.74%) babies were VLBW.In this hospital VLBW infants accounted for 47% of neonatal deaths 2,3 .
The care of ELBW neonates may impose an enormous burden on professional resources and finances of caregivers.The cost varies greatly between developed countries and developing countries and between different centres within a country or a region as it largely depends on the cost of sophisticated and advanced neonatal care and the cost of the health care system in general [4][5][6][7][8] .Consequently, it is difficult to compare the cost among different centres.In a few studies costs were calculated by dividing the total number of hospital days or ventilator days before death or discharge home by the number of survivors in order to calculate the resource use and costs incurred per survivor 7,9 .This type of data on Sri Lankan babies is largely unavailable.However, it is essential to have this information to guide forward planning, therapeutic intervention, budgeting and staffing with the aim of improving outcome.
Surfactant replacement therapy for hyaline membrane disease (HMD) in premature infants has been shown to be safe and efficacious in many studies including a study done in Sri Lanka 10 .However, surfactant therapy is extremely expensive and we may not be able to afford it as prophylaxis for HMD in the government sector.

Objectives
• To determine the outcome of ELBW babies born in CSHW during the study period • To determine the incidence of selected short term complications • To determine the average direct cost of managing such babies and The data was collected by the investigators using a pretested standard questionnaire.Clinical notes from the babies and mothers were used to collect the relevant data.The birth weight was plotted on Fenton 11 growth charts to determine whether the baby was appropriate for gestational age (AGA), small for gestational age (SGA) or large for gestational age (LGA).All the survivors of the test population were examined by a consultant ophthalmologist for retinopathy of prematurity (ROP).These children were followed up until discharge from the ophthalmology clinic and findings of this referral were entered into the questionnaire.In the neonatology unit at CSHW a cranial ultrasound scan (USS) is done in all ELBW infants at the age of 7-14 days routinely or whenever intraventricular haemorrhage (IVH) is suspected.It is performed by the consultant radiologist on duty.Repeat USS is done on discharge or at 36-40 weeks postmenstrual age.In this study we collected data related to IVH, germinal matrix haemorrhage (GMH), periventricular leukomalacia (PVL) and ventriculomegaly (mild 0.5-1cm, moderate 1.0-1.5cm,severe >1.5cm).The diagnosis of NEC was made if the baby had modified Bell's stage 2 or 3 12 .
The survival rate (percentage of babies who were live at discharge or by 40 week corrected gestational age), incidence and severity (stages 1-5) of ROP, incidence and severity of IVH, feeding method on discharge, weight gain/loss on discharge and supplemental oxygen on discharge were considered as short-term outcomes of infants.
In this study we used "average direct cost" which could be used easily to compare the costs taking into account the cost incurred on drugs as well.The incidence of selected complications was restricted to the 36 ELBW babies who survived for more than 6 hours after birth.One of the 7 babies with IVH had bilateral grade 4 IVH from which he succumbed.
Eye examination, done in the 36 ELBW babies who survived for more than 6 hours after birth, revealed the presence of ROP in 25 (83.3%)babies on first eye examination.Incidence of stages 1, 2, and 3 ROP was 60%, 16.7% and 6.7% respectively.Only 5 (16.7%) had completely normal retina on first ophthalmologic examination.None of the babies developed stages 4 or 5 ROP.
Average weight gain per survivor at discharge was 5.2g/kg/day.None of the babies were oxygen dependent or tube fed at discharge.

Discussion
Itabashi et al, in a study of 3,065 ELBW infants born in 2005 in Japan, showed that neonatal mortality rate and the mortality rate during NICU stay among ELBW infants were 13% and 17%, respectively 13 .As all the deaths in our study occurred within first 7 days of life and during ICU stay, neonatal mortality rate and the mortality rate during NICU stay can be calculated as 23% and 25.7% respectively (4 babies did not get admitted to NICU).In another study done in South Africa, overall survival rate of VLBW was 70.5% and survival rate of ELBW infants was 34.9% 14 .In our study the overall survival rate of ELBW infants was 77%.
The cost of managing ELBW infants varies between developed and developing countries and different regions within a country 4,6,15,16 .Furthermore, it is difficult to compare the costs between different centres due to vast differences in labour costs and the cost of medications.Thus it is reasonable to calculate costs in terms of hospital stay, ICU stay duration of mechanical ventilation etc. Analyzing data from 5,364 infants with birth weight 501-1000g born in USA, Walsh et al found that median duration of ventilation for survivors was 23 days 17 .In the South African study 14 , mean duration of mechanical ventilation was 8.08 days and the mean duration of supplemental oxygen was 8.2 days in VLBW babies.
In our study mean duration of mechanical ventilation and supplemental oxygen was 3.5 days and 8.9 days respectively.
Approximately 30% of VLBW premature infants have IVH and 11.4% of ELBW infants have grades 3 or 4 (severe) IVH 18 .In our study 19.4% ELBW infants had IVH and 2.7% had severe IVH.However this may be an under estimate as not all the babies who died early had cranial ultrasound scans.Only one out of the 7 babies who developed IVH had received surfactant replacement therapy compared to 6 who had not received surfactant (P<0.001).
Otherwise the complications were similar in those receiving and not receiving surfactant therapy.
UK ROP screening guidelines recommend that first ROP screening should be undertaken at 30 to 31 weeks postmenstrual age for the babies born before 27 weeks and between 4 to 5 weeks postnatal age for babies born between 27 and 32 weeks.For babies >32 weeks gestational age but with birth weight <1501g first ROP screen should be undertaken between 4 to 5 weeks 19 .In general, more than 50% of premature infants weighing less than 1250 g at birth show evidence of ROP, and about 10% of the infants develop stage 3 ROP 19 .In our cohort 25 (83.3%)showed evidence of ROP and 2 (6.7%) had stage 3 ROP.

Conclusions
• ELBW babies in this study had an overall survival rate of 77%.
• Mean duration of mechanical ventilation was 3.5 days and the mean duration of supplemental oxygen was 8.9 days.
• IVH was significantly less in babies treated with surfactant.

Limitation of the study
Small sample size is the biggest limitation of this study.

Table 1 :
Sample distribution Average direct cost was calculated by considering the duration (cost) of hospital stay per survivor (total hospital days divided by number of survivors), neonatal intensive care unit (NICU) care cost (in days per survivor), costs of continuous positive airway pressure (CPAP)/intermittent positive pressure ventilation (IPPV)/oxygen therapy (in days per survivor), cost of surfactant and cost of intravenous (IV) antibiotics.Direct fixed cost (staff salary), indirect fixed cost (salaries of administrators, paramedics etc.), indirect variable cost (cost of water, telephone, electricity, diet of parents) and capital cost (cost of land, building, instruments and equipment) were not calculated.

Table 4 : Average direct cost in Sri Lankan Rupees (SLR) Item Cost in SLR per survivor
Cost of enteral nutrition was not included as the data were not completed.None received TPN.The average direct cost in Sri Lankan rupees (SLR) is shown in table4.The incidence of selected complications is shown in table 5.